- What gets FPS?
GPUs.
What gets more FPS?
(boxes clattering)
More GPUs, obviously.
Everybody thinks so
and manufacturers have been working on this technology
since the late '90s.
So then what the heck happens to it?
I'm gonna let you in on a little secret.
Come here.
It never died and it's the future.
Now, that might seem like a bold prediction
given that NVIDIA just completely removed
the multi-GPU links from their latest generation,
even on the premium workstation cards.
But there is a clear core set for better performance
through multi-GPU graphic solutions,
and the most bizarre part is that it's Apple
who ultimately did it.
To properly see where we're going,
sometimes we have to visit the past,
which is why we got our hands
on this legendary piece of kit.
The Quantum3D Mercury brick is an eight-GPU design
from 25 years ago that has a lot more in common
with your future gaming rig than you probably realize,
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- Our story begins today
with the Quantum3D Obsidian 100SB-4440V
that Ross Tregemba thoughtfully brought along
when we shot our Voodoo 5 6000 video.
The name might not sound like much,
but it's a great example of something
that the original 3dfx Voodoo 1 was capable of,
even if it rarely did it: dual-GPU operation,
in this case, on a single board.
Now, these ones were intended for desktop PCs,
but the primary purpose of cards like this
was to drive arcade machines.
More on that later because first,
I wanna talk about the brick.
This extremely rare piece of computing history
uses a four card setup,
with each card equipped with two Voodoo 2 GPUs.
That is eight GPUs running all together
on the same workload.
Now, I know what you're thinking.
(chuckles) That looks like it would have a tough time
fitting in a PC that also needs dedicated cards for sound;
networking; and yes, 2D graphics to run the desktop
because the Voodoo 2 was 3D only,
and you'd be right about that.
But again, more on that later.
For now, it's time to see this thing in action.
I was going to be the one to install the brick
in this simulator chassis from 1999,
but, understandably, the owner didn't trust me
to do it without dropping it, so I didn't.
But we've got some B-roll of how it goes in.
It's wild.
I mean, all four cards need to go into their own PCI slots,
then it's gotta be wired up to a VGA out and in,
then it's gotta be wired up to a VGA pass through
at the back of the chassis,
then these two cables are wired up to the back
for a feature called swap lock
that allows more than one of these then-$20,000 machines
to be utilized at once.
The rest of these specs are high-end,
even if relatively mundane.
We've got dual Pentium III 500 megahertz processors,
what appears to be
an Intel first-party Extended Motherboard,
a mere 425-watt power supply
from the legendary PC Power and Cooling.
We've got 256 megs of RAM;
a gigantic sound card that's as big as some GPUs today;
and then a ton of cooling, especially for the time.
Dual 92-millimeter fans
and then a couple more 80 mils that blow directly down
onto the heat sinks over the GPUs with this,
what looks very handmade shroud.
Let's fire it up.
Ooh.
This is part of the simulator experience.
It needs to sound like it's taking off.
Wait, there's no vent for those 80-millimeter fans.
They're just-
- Yeah, it's got enough spacing in there for it just to...
- Okay, all right.
Windows NT, let's go.
We have a few options for things we can run.
We could play games on it,
which obviously is the first thing I would've done
if I worked at a military installation
and one of these showed up.
Be like, "How fast does it run Half-Life?"
But we actually also have some simulator software.
Super cool.
It's so weird seeing a Sierra splash screen
when you fire up Half-Life.
You mean valve, right?
Valve.
Okay, all the...
What the?
What the, stop.
Stop, buddy.
- [Anthony] Check out the pixelation.
- Whoa, the first thing I noticed
was that compared to the Voodoo 5 6000,
the frame rate is obviously lower.
What I didn't think to look at is how smooth it is.
What the crap?
This was possible in 1999?
- [Anthony] I think that's functionally
16 times anti-aliasing.
- This looks modern.
Cleaner than modern.
- [Anthony] It looks like a much higher resolution
than it is.
- That is wild.
I'm specifically going out of my way
to put these straight lines at just ever so slight an angle
so that I can see the stair step...
It's just not there.
It really makes the crappy old texture stand out,
doesn't it?
- [Anthony] Oh, yeah.
- If this had the horsepower to run modern games
with modern resolution textures, it would look so good.
Ah, blah, blah, blah, blah, blah, blah, blah,
blah, blah, blah, blah, blah, blah, blah, blah.
Got them.
It's hardware level anti-aliasing.
Okay, that's pretty wild.
I think I do kind of need to see it
without the hardware anti-aliasing then.
Okay, so how do you, is that something you can change
while the game is running?
- Yes.
- Oh, no way.
- Yeah, so what we're-
- No way, wait, what?
- So this is a Medusa cable.
So it's got a 26-pin guy here, two VGAs.
So what we're gonna do is we're gonna bypass this
by just plugging into one of the boards individually.
- So in this case, each board is a dual-GPU GPU
and the other three boards
are just contributing to more anti-aliasing?
- Correct.
- Got it.
- So the bridge is basically combining the image.
It's basically four instances of Voodoo 2 SLI.
- Okay. - Basically what it is.
- So I'll get the same FPS-
- Correct.
- But it'll look like
butt. - Crap.
Exactly. (laughs)
- We're both going pretty much the same place.
Slightly different stages.
I can confirm anti-aliasing no longer working.
Now, it still looks smoother than it would on an LCD
just because CRTs have, they're not really pixels.
They're more like dots.
So they're not squared at the edges,
but you can really see the difference here.
Oh, look, especially on objects that are farther away,
where the level of detail is lower,
like those picture frames, blah.
Yeah, that's a big yikes.
And the shimmering as I'm moving back and forth,
that is a big difference.
Not the kind of difference
the average home user would pay for,
but a difference nonetheless.
Let's try some simulation stuff.
- [Anthony] It's a non-interactive.
- Right, I guess I wouldn't have whatever control cockpit
they would use for something like this.
And that is smooth.
- [Anthony] 60 FPS.
- In 1999.
That's the thing we've gotta remember.
Hold on, I'm not done,
I'm not done checking out how smooth the terrain looks.
Yeah, we're seeing the. (grunts)
Whether that's a frame pacing issue
or whether that's just a VSync issue.
- [Anthony] Isn't it pretty incredible
how well the AA works in this?
- Anti-aliasing is unreal.
Look at these particle effects.
Yeah, they're not amazing or whatever, but they exist.
There's just no other way to put it,
this machine is mind blowing.
But what's most mind blowing about it, at least to me,
is that the maker of the brick, Quantum3D, still exists
as a producer of simulation hardware and software.
If you remember the Evans & Sutherland SimFUSION card
that we looked at a couple of years ago,
these guys probably would've been in competition
with that at some point.
Going back to the days of the brick though,
they sometimes sold enhanced versions
of 3dfx's single-GPU cards to enthusiasts,
with extras like additional video memory and texture units.
But their main business
was to act as 3dfx's arcade and simulation division
until they were spun off as their own company in 1997.
With that history, it makes a lot of sense
that they had the know-how to create exotic solutions
like these out of Voodoo GPUs.
The first known use of a Quantum3D card
was I.C.E. Home Run Derby in 1996,
and a lot of high profile games, like San Francisco Rush,
would go on to use them too.
These were not cheap solutions,
ending up in systems costing anywhere
from over 1,000 to thousands to in excess of $10,000.
But while it would've been unthinkable
for a home user to spend more than a few hundred dollars
on a gaming device at the time,
at the high end, Quantum3D's devices were used
for military simulation,
and even down at the low end,
they could be expected to deliver
tens of thousands of dollars of revenue for their owners
quarter-by-quarter over the lifetime of the machine.
And it's that lifetime that was one of their big advantages
because before Quantum3D,
it was quite common for arcade games
to use bespoke hardware,
or at best a platform like the Neo Geo.
By comparison, Quantum3D's platform
was more or less a PC in all but form factor,
which made changing over to a new game,
even one that requires a hardware upgrade,
much simpler and more cost effective
than it had been in the past.
Often, game data was even stored
on a bog standard IDE hard drive.
And because the Glide API that the GPUs ran on
was readily available and had a similar syntax to OpenGL,
games were much easier to prototype and develop.
Then as now, the hardware is only part of the battle
and the real work is in making it easier for developers
to get the most out of it.
And get the most out of it they did.
The additional power on tap from Quantum3D cards
could be used in one of two ways.
Either as a traditional SLI setup
where the additional GPU or GPUs
could be used to push resolutions or frame rates
higher than they would be able to otherwise;
or as was common in the simulator space,
to have multiple cards generate the same image,
but with rotated anti-aliasing patterns.
This was a way for them to output
ridiculously smooth graphics in the absence of resolution
that was high enough to prevent aliasing.
That is how the Mercury brick would've been used.
And this was actually very important because in a simulator,
hard pixel edges can be very distracting,
unlike our new Circuit Desk Pad on LTT Store.
Stealthy AF.
Now, of course, with the demise of 3dfx
came the demise of SLI as the world knew it then.
But that didn't mean that companies
like Quantum3D and Evans & Sutherland
were left without hardware to sell.
Multi-GPU development was seen as essential in the sim space
and continued in earnest,
even while there wasn't yet an official way
to make it work from major players,
be they NVIDIA or ATI.
In fact, Alienware even had a project in the works
to run multiple GPUs before new age SLI
and Crossfire came along.
When those technologies finally hit the scene though,
multi-GPU came back to the masses in a big way
with some very interesting implementations.
Early Crossfire, for example, required a master GPU
that stitched together the output from multiple GPUs,
rendering different parts of the scene
with an external dongle.
This method is called split frame rendering
and is similar in concept
to how old school SLI used to work.
It wasn't ideal though.
Even aside from the hardware complexity,
this setup limited the maximum resolution.
There was also software Crossfire at the time,
which allowed dongle-free operation
directly over the PCI-Express bus,
but PCIe wasn't as fast then as it is now
and it was only really suitable for low-end GPUs.
New age SLI and CrossfireX meanwhile
used bridges between the cards themselves,
which is actually quite similar to 3dfx's SLI.
The difference, though,
was that rather than stitching together
scan lines or quadrants of the screen,
the cards could communicate with each other over the bridge
and divide up their work
by each rendering alternating frames leading to,
you guessed it, a return to multi-GPU cards
like the GTX 590 and Radeon 6990.
Even three-way and four-way configurations
were possible using multiple bridges.
These setups were gargantuan and power hungry,
but they represented the best performance
you could get at the time and, unlike in the past,
they were available to the general consumer.
Now, while it's obviously simpler to implement,
the alternate frame rendering approach
unfortunately led to the micro-stuttering
that we became familiar with in the 2010s.
Since each GPU might complete its frame
in a slightly different amount of time,
the pacing of frame delivery could be all over the place,
resulting in impressive benchmarks
but a really poor gaming experience.
Some attempts were made to smooth out frame delivery.
NVIDIA, for example, released a high bandwidth version
of the SLI bridge that allowed the cards
to communicate more quickly,
but it just wasn't able to keep up with advancements
in monitor technology,
both in terms of resolution and refresh rate.
These niche projects were taking considerable resources
from both AMD and NVIDIA that,
along with tepid enthusiasm from game developers
who really prefer to target the lowest common denominator,
ultimately led to the demise of consumer multi-GPU.
It's not that NVIDIA gave up without a fight, though.
They actually quietly made an attempt to resurrect SLI
in the RTX 2000 generation
when they explored checkerboard frame rendering.
Unlike split frame rendering,
which would have both GPUs contributing
to each displayed frame,
but would often have an ugly seam down the middle,
CFR would divide the frame into small chunks
for each card to render,
then composite the result into a single image.
In theory, it could have been the best of all worlds
and even avoid NVIDIA having to specifically optimize
a given gain for multi-GPU,
but they ultimately abandoned it for a few reasons.
First, the processing overhead was significant,
which could increase latency.
And second, DirectX 12's explicit multi-GPU model
showed up around that time,
which handed multi-GPU control over to the game developer,
entirely offloading it from the driver,
which game developers obviously haven't done anything with.
But that doesn't mean the multi-GPU dream is dead,
and of all people, it's Apple showing us the way.
You see, the M1 series of SoCs
has far more in common with our Quantum3D brick
than meets the eye.
Have a look at these die shots and you'll see what I mean.
We could think of each of these GPU core blocks
on the M1 Pro as similar to the GPU chips on our brick.
With a fast enough interconnect,
they can act as one to render a single output,
like we see in the M1 Max.
But then, okay, nothing that we're looking at here
is really multi-GPU.
It's just a bigger single-die GPU.
It's only when we move to the M1 Ultra
that things get really interesting.
You see, the 64-core GPU in the M1 Ultra acts,
for all intents and purposes, like a single-die solution.
But Apple disclosed in their launch event
that it is actually a dual-die design
that uses a game-changing packaging solution
that they call UltraFusion.
So it's two GPUs acting as one.
It's SLI, but with absolutely none of the downsides.
How on earth did they do it?
Well, you see,
the problem has always been the interconnect speed.
See, traditionally, once you go off a single die,
your bandwidth drops dramatically.
That's why NVIDIA couldn't achieve VRAM coherency
across multiple cards via their SLI bridges.
The links were just too slow.
It's also why tricks,
like split frame or alternate frame rendering,
have always been necessary.
They couldn't just pool together the GPU resources
because the left hand would have no idea
what the right hand was doing in real-time.
But Apple did it,
and both AMD and NVIDIA have also talked publicly
about the possibility of future GPU designs
that use multiple chiplets with high speed interconnects
in order to economically scale performance.
It's coming back, baby.
But how does this factor in?
Well, the thing is, back in 1998, the bandwidth requirements
for inter-GPU communication weren't as high.
So your UltraFusion interface
could look a lot more like this.
It's really funny isn't it,
how the more things change, the more they stay the same?
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- If you guys enjoyed this video, go check out our coverage
of the Evans & Sutherland SimFUSION 6500q
for more multi-GPU madness.
That thing is really cool.